Novo Nordisk and Lilly say GLP-1 drugs slowed 'aging clocks' in trial patients — unpublished conference data

Novo Nordisk and Eli Lilly presented data over the weekend at the Aging Research & Drug Discovery conference in Boston suggesting that their GLP-1 drugs slow molecular “aging clocks”, MIT Technology Review reported on 6 October 2026.

What the companies reported

• Novo Nordisk analysed blood drawn from 10,052 people in a trial of semaglutide (Ozempic/Wegovy) — half on the drug, half on placebo — at baseline and months later, using proteomic clocks that estimate age from protein levels.
• Overall, the difference was about “two to three years” of biological age, said Novo project leader Nikolaj Roed; a clock based on heart proteins showed a slowdown of up to 4 years.
• Eli Lilly ran a smaller study of tirzepatide (Mounjaro/Zepbound) with epigenetic clocks (DNA-methylation changes) and also found that, for the most part, biological age advanced more slowly on the drug.
• The size of the effect varied widely depending on the clock and organ examined.

Why it matters — and the caveats

UCLA’s Steve Horvath, a pioneer of aging clocks, called two years “a pretty strong effect” and said the data could point to the drugs being “geroprotectors”. But:

• These are conference presentations by the manufacturers, not peer-reviewed papers.
• Participants were overweight or diabetic. “In a healthy population, no one knows,” said Harvard’s Vadim Gladyshev, who helped Novo with its measurements.
• Aging clocks are surrogate markers; whether lowering them means longer, healthier lives is not proven.
• GLP-1 drugs have side effects, including muscle loss.

A US ARPA-H-funded $38 million study in Texas will test whether semaglutide has anti-aging effects in healthy people over 60. Nobody should start these drugs for longevity without talking to a doctor.